Multi-Input Multi-Output (MIMO) technology is to improve efficiency in data transmission and reception by using multiple transmitting antennas and multiple receiving antennas instead of a single transmitting antenna and a single receiving antenna. If a single antenna is used, a receiving side receives data through a single antenna path. However, if multiple antennas are used, the receiving side receives data through various paths. Accordingly, speed and amount in data transmission may be increased, and coverage may be increased.
A single-cell MIMO operation may be divided into a single user-MIMO (SU-MIMO) scheme, in which one user equipment receives a downlink signal from one cell, and a multi user-MIMO (MU-MIMO) scheme, in which two or more user equipments receive a downlink signal from one cell.
In the meantime, a coordinated multi-point (CoMP) system for improving throughput of a user located at the cell edge by applying improved MIMO transmission under the multi-cell environment has been actively studied. If the CoMP system is applied, inter-cell interference may be reduced under the multi-cell environment, and system throughput may be improved.